Influence of Substrate Temperature on the Structural and the Electrical Properties of CdIn2Se4 Thin Films

Abstract

CdIn2Se4 thin films of different thicknesses were prepared on pre-cleaned glass substrates by the thermal evaporation technique under vacuum 10-5 Torr. The influence of substrate temperature on the structural and the electrical properties has been studied. The crystal structure and orientation of the prepared films were investigated by x-ray diffraction. The x-ray analysis confirmed that thin films of CdIn2Se4 thermally evaporated at room temperature are polycrystalline with cubic crystal structure. The films were preferred orientation along plane (202). The crystallite size (ranged between 17.8 nm and 24.7 nm) increases with increasing substrate temperature. The room temperature resistivity for the films deposited at room temperature was in the order of 107 Ωcm, which decreased to 102 Ωcm for substrate temperature at 523 K. The activation energy varied from 0.32 eV to 0.22 eV with increasing substrate temperature from 298 K to 523 K. The thermoelectric power measurements of CdIn2Se4 thin films revealed that all deposited films at different substrate temperature were n-type semiconductors. The density of charge carriers of films grown at 298 and 498 K were 7.01x1018 and 1.45x1019 cm-3 respectively.